1. Technical Background
The present invention relates to a catheter, and more particularly to a catheter with a spiral centering tip.
2. Discussion
Percutaneous transluminal coronary angioplasty (PTCA), percutaneous transluminal angioplasty (PTA), and stenting are therapeutic medical procedures used to increase blood flow through blood vessels, and can often be used as alternatives to coronary bypass surgery. In angioplasty procedures, a balloon is inflated within a narrowed or stenosed vessel, at a desired location for treatment, such as an atheroma or plaque deposit, in order to obtain an enlarged opening or lumen. In stenting, an endoluminal prosthesis of any appropriate type is implanted in the vessel to maintain patency and hold open the vessel following the procedure. In order to initiate these procedures, a physician first introduces a guidewire into a passage or lumen of a vessel to serve as a conduit for other interventional devices, such as angioplasty balloons and stent delivery systems. This guidewire is advanced to a position past the location of a stenosis. Additional interventional devices, such as angioplasty balloon catheters and stent delivery systems, are then advanced over the guidewire and positioned at the site of the stenosis, to initiate therapeutic treatment of the lesion.
A common treatment method for using such an angioplasty balloon catheter or stent delivery system is to advance the catheter into the body of a patient over the guidewire, by directing the catheter distal end percutaneously through an incision and along a body passage until the device is located within the desired site. One commonly encountered challenge with the procedure involves irregularities of the lumenal surface and narrowing of the passageway, because the distal end of the balloon catheter or the stent delivery system may “catch” on the wall surface. This may cause a challenge in reaching the desired position in the vessel, and therefore may inhibit successful treatment of the lesion. Another difficulty that may be encountered with this procedure is that once the lesion is reached, stent deployment may not be perfectly uniform if the stent delivery system is not centered within the vessel, resulting in non-uniform deployment. The end result may be reduced strength and incomplete stent scaffolding of the vessel, and a less than optimal clinical result.
The general concept of a centering catheter for treating a body vessel with a radioactive source is known in the art. See, for example, U.S. Pat. No. 6,224,535 entitled “Radiation Centering Catheters” issued May 1, 2001, and U.S. Pat. No. 6,267,775 entitled “Self-Expanding Medical Device For Centering Radioactive Treatment Sources In Body Vessels” issued Jul. 31, 2001.
However, it is desirable to provide a device for centering a balloon catheter or stent delivery system during its journey through the vasculature or other anatomy and to the treatment site, to facilitate access to tortuous anatomy, and then to promote uniform deployed stent expansion at the treatment site.
According to the principles of the present invention, a centering catheter has a distal portion which tends to remain centered during its entire journey through anatomy and toward the desired treatment site, as well as at the treatment site.
This disclosure of the present invention will include various possible features and embodiments. However, the present invention scope is set for the in each of the claims, and is not limited to the particular arrangements described in this disclosure.
An object of the present invention is to facilitate access to tortuous anatomy, so that a lesion location may be more easily reached and the vessel may be treated. Another object of the present invention is to facilitate uniform deployed stent expansion by providing a centering catheter for stabilizing a stent delivery system catheter and centering it in the vessel during stent deployment.
Centering catheters may have an elongated catheter body with a proximal end and a distal end, and at least one spiral centering device attached near the distal end of the catheter. The spiral centering device may have a proximal end and a distal end and at least one spiral strut extending therebetween. The spiral centering device has a smaller diameter for insertion into a lumen, and a larger diameter for expanding to substantially equal the diameter of the lumen and to center a distal portion of the catheter within the lumen. The spiral centering device also has a plurality of intermediate diameters, between the smaller diameter and the larger diameter. These intermediate diameters may be utilized as the spiral centering device adjusts to diameter variations in the lumen of the vessel during the catheter journey through the vasculature and toward the treatment site.
Once the site is accessed, the spiral entering centering device may also facilitate uniform stent delivery for either balloon expandable or self-expanding stents, by centering the distal end of the catheter during the deployment of the stent. Uniform stent expansion may contribute to a successful clinical outcome. The spiral centering catheter and other devices may then be withdrawn from the lumen of the vessel.
In accordance with one aspect, a catheter may have at least one spiral centering device attached near a distal end of the catheter. Each spiral centering device has a proximal end and a distal end, and at least one strut extending therebetween. Each spiral centering device may have a variable diameter that tends to center the distal end of the catheter, steering the distal portion of the catheter away from the vessel wall during its insertion through the body passage to the treatment site.
In accordance with another aspect, a stent delivery system may have at least one spiral centering device attached near the distal end of the stent delivery system. Each spiral centering device may have a proximal end and a distal end, and at least one spiral strut extending therebetween. Each spiral centering device preferably has a variable diameter that tends to center the distal end of the catheter during stent deployment.
An advantage of the present invention is that the sometimes-tortuous anatomy of the vasculature may be more easily traversed while avoiding adverse lumen contact, and access to the lesion location may be facilitated by the availability of a spiral centering device that tends to center the distal portion of the catheter throughout its introduction into the vessel or other anatomy. Another advantage of the present invention is that the spiral centering device may stabilize the distal end of the catheter during stent expansion, and may therefore allow a physician to achieve a more uniform stent expansion with resultant clinical benefits to the patient.
These and various other objects, advantages and features of the resent invention will become apparent from the following description and claims, in conjunction with the appended drawings.